Opinion of the Court
EPA designated as traditionally navigable. To establish a significant nexus, the EPA lumped the Sacketts’ lot together with the Kalispell Bay Fen, a large nearby wetland complex that the Agency regarded as “similarly situated.” According to the EPA, these properties, taken together, “significantly affect” the ecology of Priest Lake. Therefore, the EPA concluded, the Sacketts had illegally dumped soil and gravel onto “the waters of the United States.”
The Sacketts filed suit under the Administrative Procedure Act, 5 U. S. C. §702 et seq., alleging that the EPA lacked jurisdiction because any wetlands on their property were not “waters of the United States.” The District Court initially dismissed the suit, reasoning that the compliance order was not a final agency action, but this Court ultimately held that the Sacketts could bring their suit under the APA. See Sackett, 566 U. S., at 131. After seven years of additional proceedings on remand, the District Court entered summary judgment for the EPA. 2019 WL 13026870 (D Idaho, Mar. 31, 2019). The Ninth Circuit affirmed, holding that the CWA covers adjacent wetlands with a significant nexus to traditional navigable waters and that the Sacketts’ lot satisfied that standard. 8 F. 4th 1075, 1091–1093 (2021).
We granted certiorari to decide the proper test for determining whether wetlands are “waters of the United States.” 595 U. S. ___ (2022).
II
A
In defining the meaning of “the waters of the United States,” we revisit what has been “a contentious and difficult task.” National Assn. of Mfrs. v. Department of Defense, 583 U. S. ___, ___ (2018) (slip op., at 1). The phrase has sparked decades of agency action and litigation. In order to resolve the CWA’s applicability to wetlands, we begin by reviewing this history.
